Field of the Invention
The present disclosure relates to a liquid ejection head and a method for manufacturing a flow passage member of the liquid ejection head. In particular, the present disclosure relates to technology for forming a flow passage member by adding a filler to a structural material, e.g., resin.
Description of the Related Art
An inkjet recording head (hereafter also simply referred to as a recording head), in which a support member for supporting a substrate provided with an energy-generating element is formed by filling a resin with a filler, is known as an example of a liquid ejection head. Japanese Patent Laid-Open No. 2010-247508 discloses that in a recording head, a support member for supporting a substrate is formed by filling a resin with a filler. In forming the support member, the use of a filler reduces the linear expansion coefficient and, thereby, the stress generated between the support member and the substrate to be bonded is reduced.
The support member described in Japanese Patent Laid-Open No. 2010-247508 is formed to be provided with a flow passage for the purpose of ensuring ink communication between an ink supply chamber and the substrate and is produced inexpensively compared with alumina, which is commonly used as a material for forming the support member.
However, in the case of the above-described support member, in which the flow passage member provided with a flow passage disposed to come into contact with a liquid, e.g., ink, is formed by filling a formed material, e.g., a resin, with a filler, the filler particles are exposed at the surface of the formed material and may be dissolved into the liquid, e.g., the ink. In particular, in the case where a relatively large amount of filler is added so as to realize a small linear expansion coefficient, the filler is exposed at the surface and is easily dissolved into the liquid. The filler dissolved into the liquid, as described above, may exert harmful effects, e.g., clogging of a recording head nozzle.